From owner-freebsd-hackers Sat Mar 7 23:30:41 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id XAA18994 for freebsd-hackers-outgoing; Sat, 7 Mar 1998 23:30:41 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id XAA18952 for ; Sat, 7 Mar 1998 23:30:32 -0800 (PST) (envelope-from julian@whistle.com) Received: (from daemon@localhost) by alpo.whistle.com (8.8.5/8.8.5) id XAA24535; Sat, 7 Mar 1998 23:21:09 -0800 (PST) Received: from UNKNOWN(), claiming to be "current1.whistle.com" via SMTP by alpo.whistle.com, id smtpd024520; Sat Mar 7 23:20:59 1998 Date: Sat, 7 Mar 1998 23:16:43 -0800 (PST) From: Julian Elischer To: Marc Slemko cc: Mike Smith , hackers@FreeBSD.ORG Subject: Re: kernel wishlist for web server performance In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > Let me put it this way: how else do you propose to do copy avoidance to > avoid an extra copy going into the mbufs? The data must go from the > buffer cache to the network without any copy other than to the network > card itself. Why is your other method of doing this any less of a hack? [...] I would like to add here that in FreeBSD's unified VM/Buffer cache, a mmapped file IS the buffer cache so that a send() from an mmapped file IS copying direct fromt he buffer cache. Ther eis ONE copy.. that from the buffer cache, into the mbuf. (assuming that the data got into the memory via DMA in the first place..) you may need to have a subprocess go through and tuch all the pages to get them into ram first.. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message